This invention relates to a friction pad for use in disc brakes of a vehicle or the like.
Some prior art disc brakes utilize sintered metal as the material for the linings of friction pads. However, there are shortcomings in the use of such material, for example that only a portion of the surface thereof contacts a disc in the initial stage of usage so that the braking efficiency is relatively low.
In order to avoid the aforementioned shortcomings, it has been proposed to apply a coating of rubber or synthetic resin material to the surface of the friction pad. However, when the coating has worn, the frictional coefficient will sometimes decrease thereby decreasing the braking function.
It has also been proposed to provide an oxide layer on or adjacent to the working surface of the friction pad or the lining. However, for forming the oxide layer, the friction pad is baked at a high temperature such as 700.degree. C. or the like, and such high temperature tends to lower the bonding strength between the lining and the backing plate of the friction pad, and it is difficult to control the thickness of the oxide layer. Thus there are shortcomings in that the quality of the friction pad is not reliable, and the amount of the wear will increase when the quality is degraded.